Perceptions of adolescents and young people regarding endemic dental fluorosis in a rural area of Brazil: psychosocial suffering

Severe dental fluorosis is endemic in some rural areas of Brazil. This paper describes the psychosocial consequences of this condition and how it has affected the self-esteem of adolescents and young people in a rural area in Brazil. Semi-structured, face-to-face interviews were carried out with 23 adolescents and young people affected by severe dental fluorosis and 14 of their teachers. The study revealed the affected individuals were embarrassed to smile at strangers due to a presumed association between fluorosis and a lack of dental hygiene. Further findings include conflicts between affected and non-affected students at school, problems in pursuing a romantic relationship and uncertainties regarding a professional future. Disbelief and scepticism were observed regarding the ethical position that science can offer a solution to the problems stemming from the disease. Lesions from severe dental fluorosis appear to be a stigmatising factor and have contributed toward suffering and self-exclusion among an entire generation of adolescents and young people.     

Identification of swainsonine as a glycoside inhibitor responsible for Sida carpinifolia poisoning

The indolizidine alkaloid swainsonine has been identified as the toxic constituent of Sida carpinifolia, a native perennial shrub-like plant, reported to produce neurological disorders in goats and ponies in southern Brazil. Swainsonine was detected in dry ground plant material after extraction and analysis by both liquid and gas chromatography mass spectrometry. The swainsonine concentration was 0.006% on a dry weight basis. The clinical and pathological features of this lysosomal storage disease were similar to those observed in Swainsona, Oxytropis, Astragalus, and Ipomoea poisonings with multiple cytoplasm vacuoles in neurons, acinar pancreatic cells, hepatocytes, and renal tubular cells.     

Expression of nitric oxide synthases and in vitro migration of eosinophils from allergic rhinitis subjects

The expression of nitric oxide (NO) synthases and the role of the NO cyclic GMP pathway on the migration of eosinophils from untreated patients with allergic rhinitis were investigated. Inducible NO synthase was strongly expressed in eosinophils from healthy individuals, but not in eosinophils from allergic rhinitis patients. The neuronal isoform was observed in eosinophils from each group studied, whereas no staining for the endothelial isoform was detected in either group. The chemotaxis to N-formyl-methionyl-leucyl-phenylalanine (fMLP, 5 x 10(-7) M) and eotaxin (100 ng/ml) was significantly potentiated in allergic rhinitis eosinophils. In both groups, N(omega)-nitro-L-arginine methyl ester (L-NAME, 1.0 mM) or 1H(1,2,4)-oxadiazolo(4,3,-a)quinoxalin-1-one (ODQ, 0.2 mM) markedly reduced the chemotaxis. The selective iNOS inhibitor N-(3-(aminomethyl)benzyl)acetamidine (1400 W, 0.1-1.0 mM) significantly reduced the chemotaxis of eosinophils from healthy but not from allergic rhinitis subjects. The inhibition by L-NAME was restored by 3-morpholinosydnonimine (SIN-1) and S-nitroso-N-acetyl-penicillamine, whereas the inhibition by ODQ was restored by dibutyryl cyclic GMP. In conclusion, both endothelial and inducible NO synthase isoforms are absent in allergic rhinitis eosinophils, suggesting that the NO cyclic GMP pathway in this cell type is maintained through the activity of a neuronal isoform.     

The nicotinic allosteric potentiating ligand galantamine facilitates synaptic transmission in the mammalian central nervous system

In this study, the patch-clamp technique was used to determine the effects of galantamine, a cholinesterase inhibitor and a nicotinic allosteric potentiating ligand (APL) used for treatment of Alzheimer's disease, on synaptic transmission in brain slices. In rat hippocampal and human cerebral cortical slices, 1 microM galantamine, acting as a nicotinic APL, increased gamma-aminobutyric acid (GABA) release triggered by 10 microM acetylcholine (ACh). Likewise, 1 microM galantamine, acting as an APL on presynaptically located nicotinic receptors (nAChRs) that are tonically active, potentiated glutamatergic or GABA-ergic transmission between Schaffer collaterals and CA1 neurons in rat hippocampal slices. The cholinesterase inhibitors rivastigmine, donepezil, and metrifonate, which are devoid of nicotinic APL action, did not affect synaptic transmission. Exogenous application of ACh indicated that high and low levels of nAChR activation in the Schaffer collaterals inhibit and facilitate, respectively, glutamate release onto CA1 neurons. The finding then that the nAChR antagonists methyllycaconitine and dihydro-beta-erythroidine facilitated glutamatergic transmission between Schaffer collaterals and CA1 neurons indicated that in a single hippocampal slice, the inhibitory action of strongly, tonically activated nAChRs in some glutamatergic fibers prevails over the facilitatory action of weakly, tonically activated nAChRs in other glutamatergic fibers synapsing onto a given neuron. Galantamine is known to sensitize nAChRs to activation by low, but not high agonist concentrations. Therefore, at 1 microM, galantamine is likely to increase facilitation of synaptic transmission by weakly, tonically activated nAChRs just enough to override inhibition by strongly, tonically activated nAChRs. In conclusion, the nicotinic APL action can be an important determinant of the therapeutic effectiveness of galantamine.     

Surface characteristics of implants influence their bone integration after simultaneous placement of implant and GBR membrane

The purpose of this study was to evaluate the influence of titanium surface characteristics on bone integration of implants, and to describe the pattern of peri-implant tissue healing after simultaneous implant placement and guided bone regeneration. In four healthy mongrel dogs mandibular premolars were extracted. Two weeks following full mouth prophylaxis and 4 months after extractions, simultaneous membrane and implant surgeries were performed. Efforts were made to produce bony defects with dimensions of 7 x 7 x 7 mm. Into these, 24 standard ITI implants (diameter = 4.1 mm; length = 8 mm) with either a titanium plasma-sprayed (TPS) or a machined surface (MS) were placed. Although implants were inserted 4 mm into cancellous bone, difficulties in achieving optimal primary stability were encountered. All dogs were maintained on a soft diet. Chlorhexidine rinses were performed three times a week. Full mouth prophylaxis was performed every 2 weeks. In the case of membrane exposure, the membranes were removed prematurely (4-6 or 14-15 weeks after surgery). Two dogs were sacrificed at 16 weeks and two at 24 weeks after surgery. Nondecalcified histologic sections were processed and histometric analyses were carried out. When membranes were removed after 4-6 weeks, a vertical bone growth (VB) of 45-61% of the original defect was noted. After membrane removal at 14-15 weeks, similar VB was observed. However, if membranes were left in situ for 24 weeks, VB was between 79% and 96%. In this group of sites, the VB was 66% at 16 weeks and 86% at 24 weeks. Osseointegration in the regenerated bone area ranged from 12% to 32% for the TPS and from 0.0% to 3.6% for the MS implants at 16 and 24 weeks combined. Osseointegration in the pristine host bone area ranged from 16% to 35% for the TPS and from 0.0% to 11% for the MS sites at 16 and 24 weeks. In conclusion, the fraction of implant-bone integration was much higher in the pristine bone compared to that in the regenerated bone. TPS surfaces positively influenced the fraction of osseointegration in comparison to MS surfaces for both regenerated and pristine bone. Furthermore, early membrane removal negatively affected the fraction of bone defect fill.     

The male biological clock is ticking: a review of the literature

The term biological clock is usually used by physicians and psychologists to refer to the declining fertility, increasing risk of fetal birth defects and alterations to hormone levels experienced by women as they age. Female fecundity declines slowly after the age of 30 years and more rapidly after 40 and is considered the main limiting factor in treating infertility. However, there are several scientific reports, chapters in books and review articles suggesting that men may also have a biological clock. The aim of our study was to conduct a review of the literature, based on the Medical Literature Analysis and Retrieval System Online (Medline), to evaluate the male biological clock. After adjustments for other factors, the data demonstrate that the likelihood that a fertile couple will take more than 12 months to conceive nearly doubles from 8% when the man is < 25 years old to 15% when he is > 35 years old. Thus, paternal age is a further factor to be taken into account when deciding on the prognosis for infertile couples. Also, increasing male age is associated with a significant decline in fertility (five times longer to achieve pregnancy at the age of 45 years). Patients and their physicians therefore need to understand the effects of the male biological clock on sexual and reproductive health, in that it leads to erectile dysfunction and male infertility, as well as its potential implications for important medical conditions such as diabetes and cardiovascular diseases.     

Psychometric properties of the Dundee Ready Educational Environment Measure (DREEM) applied to medical residents

The Dundee Ready Educational Environment Measure (DREEM) is a measure of students' perceptions of the educational environment, but its performance in evaluating the educational environment in the residency setting has not yet been described. This study aimed at describing the psychometric performance of DREEM applied to medical residents. DREEM was applied to 97 residents from 12 training programs on four specialties in six institutions in three Brazilian cities. Psychometric measures included factor analysis, Cronbach's alpha coefficients, item-to-total correlations, t-test comparisons of scores between genders, institutions, specialties, and programs, correlations with the global score of the Quality of School Life Scale (concurrent validity), and test-retest reliability. Generalizability theory procedures were applied to a random subset of data. Programs (8) were the objects of measure, while institutions (6), specialties (4), raters-within-programs (40), and items-on-the-scale (50) were facets. Variance components, generalizability (G) and dependability (D) coefficients were calculated. Cronbach's alpha was 0.93. DREEM showed high discriminant and concurrent validities. Test-retest reliability was moderate. Interactions between programs, raters and items accounted for 68% of the total variance. G and D coefficients were 0.95 and 0.67, respectively. The instrument proved to be useful for relative comparisons at both resident and program level.